怀孕 (huái yùn) literally means 'to embrace pregnancy' — the character 怀 (huái) conveys holding or carrying close to the body, like cradling something precious, while 孕 (yùn) specifically means 'to be pregnant' or 'to carry a fetus.' Together, they form the standard, neutral verb for 'to be pregnant' in Modern Standard Chinese. It is used exclusively for humans and is not applied to animals (for which terms like 怀崽 huái zǎi are used).

This word appears frequently in medical, family, and everyday contexts — for example, when discussing prenatal care, announcing a pregnancy, or describing physical changes. It’s formal enough for clinical settings yet common in casual speech among friends and family. Unlike some colloquial alternatives (e.g., 有喜 yǒu xǐ, 'to have joy'), 怀孕 carries no strong stylistic register and is appropriate across most situations.